1. Technical Field
This invention relates to a golf ball having improved flight performance.
2. Background Art
As is well known in the art, in order that a golf ball which was launched gets a long travel distance, the high rebound of the ball itself and the reduced air resistance during flight due to dimples arranged on the ball surface are crucial factors. A number of methods have been proposed for arranging dimples on the entire ball surface at as high a density and as uniformly as possible to reduce the air resistance.
Most often the dimples are recesses or dips of a circular shape as viewed in plane. Even when the width of a land partitioning two adjacent dimples is reduced to nearly zero in order to arrange circular dimples at a higher density, the zone surrounded by three or four dimples becomes a land of generally triangular or tetragonal shape having a certain area. Since it is requisite that circular dimples be arranged on the spherical surface as uniformly as possible, the design effort must reach a certain compromise on the distribution density of circular dimples.
Under the circumstances, it would be desirable to arrange dimples at a higher density and uniformly. To this end, JP-A 2001-212260 proposes that dimples of about two to five types having different diameters are arranged on the spherical surface of a ball which is assumed to be a regular octahedron or regular icosahedron.
However, as long as circular dimples are used, the percent occupation of the total of dimple areas on the overall spherical surface area has a practical limit of about 75% (the total of land areas accounting for about 25% of the overall spherical surface area). It is then desired that in order to arrange dimples on the ball surface so as to further reduce the air resistance of the ball in flight, the percent occupation of the total of dimple areas on the overall spherical surface area be further improved.